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Customer Success Story

Line surge arresters improving reliability of network in the United States



Extra-high voltage (EHV) lines act as a 'backbone' for electricity transmission networks. Voltage surges due to lightning strikes and switching events put reliability of these EHV lines at risk. To meet this challenge, one of the leading power utilities in the USA selected Hitachi Energy's line surge arrester solution using Externally Gapped Line Arresters (EGLA).

Customer Highlights

Established in 1906, American Electric Power (AEP) is a major power utility in the United States. The company serves more than 5.5 million customers across a geographical area of more than 500,000 square kilometers. The high voltage power transmission network of AEP, running for over 63,000 kilometers and one of the longest in the US, includes extra-high voltage (EHV) lines, operating at voltages as high as 765 kilovolts (kV). These EHV lines facilitate the transfer of large amount of electricity over long distances.

Lightning strikes can result into excessive overvoltage stress across these lines. Such stress can damage assets of power transmission system, like transformers and switchgear, potentially leading to an interruption in electricity supply.


Hitachi Energy offered its PEXLINK line surge arrester concept as a solution to AEP to maintain reliability of EHV network. The solution uses an Externally Gapped Line Arrester (EGLA), with a disconnection device and remote monitor.


Hitachi Energy’s EGLA is designed as a universal solution with a compact, adaptable design suitable for installation on multiple types of transmission tower designs with minimal adjustment needed. The installation is fast and simple with proven, robust hardware. EGLA also includes an automatic overload disconnection and visual indication, making it easy to identify and replace a failed unit in time. It is possible to monitor EGLA from ground level, assuring personnel safety.


Main data
Year of installation 2021
Type of product PEXLINK solution with Externally Gapped Line Arresters (EGLA)
Number of units 12 units on 4 EHV towers
Voltage 765 kV
Frequency 60 Hz